wifi: mac80211: add RCU _check() link access variants

We might sometimes need to use RCU and locking in the same code
path, so add the two variants link_conf_dereference_check() and
link_sta_dereference_check().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/mac80211.h

@@ -1915,6 +1915,10 @@ static inline bool lockdep_vif_mutex_held(struct ieee80211_vif *vif)
 	rcu_dereference_protected((vif)->link_conf[link_id],	\
 				  lockdep_vif_mutex_held(vif))
 
+#define link_conf_dereference_check(vif, link_id)		\
+	rcu_dereference_check((vif)->link_conf[link_id],	\
+			      lockdep_vif_mutex_held(vif))
+
 /**
  * enum ieee80211_key_flags - key flags
  *
@@ -2311,6 +2315,10 @@ static inline bool lockdep_sta_mutex_held(struct ieee80211_sta *pubsta)
 	rcu_dereference_protected((sta)->link[link_id],		\
 				  lockdep_sta_mutex_held(sta))
 
+#define link_sta_dereference_check(sta, link_id)		\
+	rcu_dereference_check((sta)->link[link_id],		\
+			      lockdep_sta_mutex_held(sta))
+
 #define for_each_sta_active_link(vif, sta, link_sta, link_id)			\
 	for (link_id = 0; link_id < ARRAY_SIZE((sta)->link); link_id++)		\
 		if ((!(vif)->active_links ||					\